Many latching mechanisms have been proposed for securing hoods to the car body. Today with the emphasis on economy, proposals have attempted to simplify the mechanism. However, in the search for greater economy and simplicity, safety may be jeopardized. For example, where the latching mechanisms are frozen, parts may be frozen in a non-securing position and when the latch may be thought by the driver occupant to be fully secured, it may in fact not be so and the hood may suddenly fly open causing a very dangerous situation. These and other such like situations must be prevented.
U.S. Pat. No. 3,565,476 teaches a hood latch mechanism of complicated construction incorporating four separate components unlatched by a solenoid, having primary and secondary latching means released by a solenoid via a primary release lever engaging a pawl detent.
U.S. Pat. No. 4,203,621 discloses a latching mechanism having first and second latching means. Neither device is simple nor incorporates a co-operative positive secondary latching means which blocks the guide channel within the U-shaped housing upon accidental release of the striker by the primary latch.
U.S. Pat. No. 4,298,223 and United Kingdom Patent Application 2,061,369 each teach a simplified mechanism having a primary latch with a forwardly-biased secondary keeper preventing the primary latch from releasing until such time as the secondary keeper is disengaged. Again neither device blocks the guide channel within the U-shaped housing upon accidental release of the striker by the latch. Further, in neither device does a cooperative rearward stop mechanism exist for preventing over-rotation and hence potential damage for the ratchet mechanism.
Canadian Letters Patents 966,878 and 655,575 teach a simplified mechanism having a primary latch with a rearwardly-biased secondary keeper which may be remotely actuated, again having the aforementioned deficiency with no safety mechanisms therein incorporated.
Canadian Letters Patent 237,847 embodies a latch which may be used externally or internally again having no provision for accidental release, or co-operative engagement. U.S. Pat. No. 3,378,289 discloses a latch mechanism for hoods and deck latches, each having a rotatable safety catch 108 (see FIG. 2) which co-operates with the actuation means of the device. Further, a stop mechanism arm 50 restricting the movement of latch member 46 is incorporated therein. However, the device has several primary components making the cost of manufacture in today's economy prohibitive. Further, the risk of mechanical failure for the system increases with the number of components thereof.
In Canadian Patent Application Serial Number 521,738 there is disclosed a latch mechanism comprising:
(a) a mounting plate carrying a slot having a bottom and mouth, PA1 (b) a pivotably biased pawl mechanism comprising a top arm portion for pivoting from a position over the slot to a position spaced from it, a bottom arm portion and follower means, PA1 (c) a ratchet mechanism biased for rotation and carrying a notch having a mouth and control means for controlling the follower means of the pawl mechanism, and PA1 (d) stop means for stopping rotation of the ratchet mechanism with the mouth of the notch proximate the mouth of the slot both directed towards the top arm portion of the pawl, PA1 (a) lock the ratchet mechanism with any striker in the slot and notch at the bottom of the slot with the top arm covering the slot mouth, and PA1 (b) ensure the top arm portion cannot be pushed away from over the slot unless the mouth of the notch and mouth of the slot are both proximate one another and directed toward the top arm portion.
the top arm portion normally positioned over the slot and being precluded from movement away from the slot unless the mouth of the notch and mouth of the slot are both directed towards the top arm portion.
The control means for controlling the follower means of the pawl mechanism may comprise a control surface on the ratchet mechanism and the follower means comprises a detent carried at the side edge of the pawl mechanism to engage the control surface to:
The control means for controlling the follower means may also comprise a control structure or formation carried by the ratchet mechanism (for example a slot formation through the body of the ratchet mechanism, for example a Z-shaped slot) and the follower means comprises a pin carried by the pawl mechanism (in one embodiment, the bottom arm portion).
However, even though the said proposals were improvements over prior art developments, they still had several disadvantages. If the primary pivot of the pawl were to break, the striker could fly up and the hood would be released. It is therefore an object of this invention to provide a latch mechanism of simplified construction which reduces the number of components therein, and provides all the necessary safety attributes, enhancing the locking and mechanical reliability of the latch.